If during the installation of any game you encounter errors (especially Xdelta or Unarc.dll), try the following steps:
1. Install necessary system software.
Microsoft Visual C++ 2005, Microsoft Visual C++ 2008, Microsoft Visual C++ 2010, Microsoft Visual C++ 2012, Microsoft Visual C++ 2013, Microsoft Visual C++ 2015, Microsoft Visual C++ 2017, Microsoft Visual C++ 2019 (both x86 and x64 versions),
NET Framework 3.5, NET Framework 4
DirectX 9, DirectX 10, DirectX 11, DirectX 12.
2. If Downloaded Game is in ISO file it is much easier to mount it with DAEMON Tools Lite (Virtual CD/DVD creator) (Download here) than extract it with WinRaR or 7zip.
3. Disable antivirus software (while installing)- it may falsely trigger and stop installing the game or prevent to run game. When game is installed add the installed games directory to Avtivirus exlusion list (Important).
4. Disable UAC (User Account Control) - it can block game installer.
5. Make sure that you enough space on hard drive.
6. If Game does not run right click on games shortcut and "Run as adminstartor"
7. In Windows system folder (/Windows/System32) find "unarc.dll" and delete it
8. Run the installer with the rights as shown in the picture (the menu "Properties" by right-clicking on the file):